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Altera_Forum
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14 years ago

CONF_DONE failed to go high Stratix IV

Hello Gurus

I am having hard time while trying to program the FPGA with Altera USB blaster cable. The Stratix IV FPGA is the only component in my JTAG chain. Yet, I can program the device 10% of time only, rest 90% I get the "CONF_DONE failed to go high" message. I have an LED connected to the CONF_DONE pin (forward voltage 2 V, DC current 20 mA) and it is pulled high with to 3.0V with a 750 pull-up ohm. An illustrative picture of schematics is attached.

Please comment on possible cause of this problem; may be I should put a small cap on CONF_DONE because it is rising too fast or too slow for JTAG? The PORSEL pin in my design is tied to 3 V. How can I measure ramp up time of VCCPGM from 0 to 3 V?

Thanks!

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    the config done pin usually has a 10K pullup on it and no LED. I would suggest removing R57 and replacing R49 with a 10K resistor, then seeing if you get better results. I think people have seen in the past that connecting LED's directly to the CONF_DONE pins causes problems, rather connect them through a FET is a better practice. Just my $.02

    Kevin